The guy who discovered the power of expressive writing is James Pennebaker, a psychologist at the University of Texas. Reading about his early experiments, you would think that writing in a journal was an antidepressant — which, functionally, it is.

... college students wrote for 15 minutes on 4 consecutive days about 'the most traumatic or upsetting experiences' of their entire lives, while controls wrote about superficial topics (such as their room or their shoes). Participants who wrote about their deepest thoughts and feelings reported significant benefits in both objectively assessed and self-reported physical health 4 months later, with less frequent visits to the health centre and a trend towards fewer days out of role owing to illness.

Incredible, right? Pennebaker's work set the precedent for researching expressive writing. In following studies, participants would write about a difficult event in their lives for 15-20 minute sessions over the course of about four days. While the subjects didn't exactly find the process fun, they did find it meaningful.

A typical prompt looks like this, though feel free to scroll through if you're short on time.

For the next 4 days, I would like you to write your very deepest thoughts and feelings about the most traumatic experience of your entire life or an extremely important emotional issue that has affected you and your life. In your writing, I'd like you to really let go and explore your deepest emotions and thoughts. You might tie your topic to your relationships with others, including parents, lovers, friends or relatives; to your past, your present or your future; or to who you have been, who you would like to be or who you are now. You may write about the same general issues or experiences on all days of writing or about different topics each day. All of your writing will be completely confidential.

Don't worry about spelling, grammar or sentence structure. The only rule is that once you begin writing, you continue until the time is up.

Why expressive writing is so healthy

The foremost reason is disclosure. Psychologists are basically in agreement that avoiding or inhibiting unpleasant emotions or suppressing your thoughts makes makes your body tense, your mood negative, and your cognition impaired. But if you access, express, and process those blocked-up emotions, you'll feel better, in all of the ways. For the same reason that talking about your breakup with your best friend makes you feel better, journaling about getting fired lets you process it.

Another facet of this is meaning. Holocaust survivor and formative psychologist Viktor Frankl helped found the field of logotherapy, or meaning therapy. The premise at the center of logotherapy is that meaning — rather than pleasure or power — is at center of human life.

This is also the role of expressive writing: Writing about your traumatic experiences — a breakup, getting fired, moving cities — allows you to uncover the meaning in them. That sense of meaning is a positive tool: Frankl's sense of meaning, reinforced by this very theory, saw him through the concentration camps of Auschwitz and Dachau.

But you work in an office.

Reflective writing can help there too.

Harvard Business School psychologist Francesca Gino and her colleagues have recently published a paper about how fitting in 15 minutes of reflection to the end of your day makes you more effective. In one field experiment, new employees who had 15 minutes to write and reflect at the end of the day performed 22.8% percent better than those who didn't.

"When people have the opportunity to reflect, they experience a boost in self-efficacy," Gino says. "They feel more confident that they can achieve things. As a result, they put more effort into what they're doing and what they learn."

The takeaways: If you reflect on your work, you can identify best practices as they emerge. If you reflect on your life, you can find the meaning you otherwise overlooked.